Opening hours at many Kent libraries could be cut as part of a cost-cutting measure aimed at saving £1 million.
The plans could involve a significant number of libraries opening for less time under a three-year strategy due to go out to public consultation.
However, council chiefs say the shake-up does not involve the closure of any libraries and some could open for longer.
A report setting out the proposals says the council needs to take steps to account for changes in the way people use its 99 libraries.
It states: "Kent County Council along with all local authorities is facing a period of unprecedented financial pressure which demands continued and sustained innovation, change and focus on positive outcomes from all services.”
The service has already saved £6m since 2013-14 and needs to save a further £1m over the next two years.
Under the strategy, libraries will be grouped according to an assessment of how well used they are throughout the day.
Their opening hours will then be adjusted - based on the number of people coming through the doors.
Library chiefs have already drawn up indicative opening hours and some could see substantial reductions.
Of the 99 libraries, about one in four will see their hours increase.
Ashford library could see its hours cut from 55 a week to 42; Dartford could be reduced to 42 hours from 57.5; Maidstone to 42 from 55; Dover could open for 37 hours a week - a decrease of 18 hours.
Tenterden library could be open for 28 hours - 21.5 hours less than now.
But there could be increases for some, mainly smaller libraries, such as Marden where the opening hours could increase to 28 from the current 18 hours.
Greenhithe library in north Kent could also gain, with opening hours more than doubling to 28 hours.
In a statement, the county council said it had to respond to changes in the way people used libraries, coupled with financial pressures.
“We know that our library service is highly-valued by the public.
"Kent is a changing county and how people use services is changing. We also cannot ignore the financial pressures on all county council services.”
"Being open at times when libraries are not well used is not a good use of taxpayers' money" - Kent County Council
The shake-up was aimed at securing the long-term future of the service.
“This will see the service maintain its key community buildings, 99 libraries, our archive centre and register offices.”
Libraries would be open at times when they were most used, the council said.
“Being open at times when libraries are not well used is not a good use of taxpayers’ money," said the council report.
"We know that visits to our libraries across the county have been falling and data from August this year found that our busiest time was between 10am - noon, accounting for 29.4% of our visits, while our quietest time was 5pm to 8pm, accounting for just 4.9% of visits.”
Libraries could share buildings with other services, the council said.
“We will work to ensure that we maximise the use of our buildings through co-locating and sharing buildings with other services,” the report stated.
The strategy says specialist services, such as mobile libraries, audio books by post and residential home services, will be maintained.
The plans will go out to public consultation for ten weeks, starting on November 21.
It will involve drop-in events at libraries across the county for people to come and talk to staff about the proposals.
Details of the changes proposed will be on the county council's website at www.kent.gov.uk/lrastrategy